Planes

Planes are universes in the multiverse, otherwise known as Dominia. Divided by the Æther, both natural and artificial planes exists in parallel.
The space between planes is referred to as the Blind Eternities. All planes intersect at one point called the Song of Dominia. The Song of Dominia is somewhat of a nickname for Dominaria.

Contents

Natural Planes

Natural planes are not created and may be as old as the multiverse itself. Natural planes are the only planes that can last forever; all other planes eventually collapse.

Natural planes are usually large, containing numerous celestial bodies, but most are devoid of life except for one planet that has the highest concentration of mana in the plane. In general, that mana rich planet shares the same name as the plane. Alara is an exception to this rule because it was split into 5 "shards", each with life flourishing, although with a deficit of two colors of mana.

Artificial Planes

Artificial planes are created by planeswalkers. Any artificial plane will eventually collapse, and all matter in the plane will be converted to energy.

An artificial plane usually contains only one planet or solar system, but some planes, such as Serra's Realm, don't contain planets at all. Artificial planes are usually inhabited by creatures created by the planeswalker who created the plane or by creatures 'borrowed' from other planes.

Planar travel

Planeswalkers

Planeswalkers are capable of transporting between planes using the power of their magical spark. They are also able to summon creatures and spells from one plane to another. However, in the Time Spiral story, Venser realizes that he too can Planeswalk even though he does not have the magical energies of a planeswalker.

Gates and Portals

On some planes there are artificial gates and portals which make artificial planeswalking possible. While one-off portals existed between Rath and Mercadia, Ulgrotha and Dominaria, and Rabiah and Wildfire, the Thran developed a set of portals consistent in design and behavior. These were later twisted by Yawgmoth to create Phyrexian portals that required the sacrifice of creatures, artifacts or a great deal of magical energy, and lead all across the multiverse. Also with the help of Lord Ith, Jodah Archmage Eaternal created a mana based portal that could transport between planes which linking portals were already established. The Artificer Venser, was able to create a planeswalking Machine to simulate planeswalking and travel between planes.

Rathi overlay

During the Phyrexian Invasion of Dominaria, the inhabitants of Urborg were taken aback when Phyrexian forces seemingly materialized out of thin air. In fact, the artificial plane of Rath had been slowly producing an artificial substance known as flowstone for an undetermined amount of time. This psionically reactive mineral increased the 'planar density' of Rath to the point that it mimicked that of Dominaria. When this occurred, the two planes started to converge, with disastrous results.

Some other remarks

During The Dark the Pretender Mairsil ordered a great Calendar drawn up to show when the paths to the Dark Lands of Phyrexia were strongest.

On Ulgrotha the planeswalker Feroz created Feroz's Ban, a magical force field, to restore the plane and protecting it from other planeswalkers. A similar barrier was created on Shandalar by the planeswalker Kenan Sahrmal.

On Kaladesh, the inventor Rashmi unwittingly created a planar bridge, a magical device powered by aether that can open artificial portals. However, she was only able to create a version that can safely transport inorganic material; living matter is violently scattered across the Blind Eternities if it attempts to use this portal. This device was stolen by Tezzeret on behalf of Nicol Bolas, after he had forced Rashmi to create a suitably large-scale version.